Manhole covers are known in the art. A conventional manhole cover is a removable plate forming the lid over the opening of a manhole to prevent anyone from falling in, and to keep unauthorized persons out of, the sewers below. Manhole covers are usually made out of cast iron. Cast iron is used for its strength, rigidity and durability. However, the use of cast iron causes conventional manhole covers to often weigh in excess of 50 kg.
While the substantial weight of a conventional cast iron manhole cover helps to keep them in place when traffic passes over them, this weight also causes difficulties when authorized personnel try to remove manhole covers for access to the sewers below. To help alleviate the difficulties of removing manhole covers, many manhole covers have at least one pick hole therein which allowed the hook end of a manhole hook to protrude below the surface of the manhole. One drawback to this design was that it allowed for air transfer through the pick hole that allowed odors and gasses to escape the sewers below. To alleviate this problem, more modern manhole covers have a pair of pick hole slots positioned in the periphery of the manhole cover and across from each other. These pick hole slots are covered by a rubber seal which does not allow for open air transfer between the sewer below the manhole cover and the environment. This arrangement prevents methane gas from releasing into the environment. This arrangement further serves as a means to separate storm water (which does not require wastewater treatment facilities) from draining through the open pick holes into the sanitary sewer system (which does require wastewater treatment facilities).
The modern manhole cover arrangement with the pick hole slots and the rubber seal has rendered conventional manhole hooks ineffective. As such, problems still remain.
One problem with the use of conventional manhole cover picks is that the process is very labor intensive and requires a lot of strength and effort to remove the manhole cover due to its weight.
Another problem with the use of conventional manhole cover picks is that the picks easily slide out of the pick holes which often leads to accident and injury.
Another problem with the use of conventional manhole cover picks is that the picks are ineffective in removing modern manhole covers.
Thus, it is a primary object of the present invention to provide an improved manhole cover lift device.
Another object of the present invention is to provide an improved method of removing a manhole cover.
Yet another object of the present invention is to provide a device that improves the ergonomics of removing a manhole cover.
Yet another object of the present invention is to provide a device that reduces the amount of strength and energy required to remove manhole covers.
Yet another object of the present invention is to provide a manhole cover removal device that is self adjusting to various sized manhole covers.
Yet another object of the present invention is to provide an efficient method and means for removing sealed manhole covers with opposing pick hole slots.
These and other objects, features, or advantages of the present invention will become apparent from the specification, drawings and the claims.